The ring-expansion metathesis polymerization of cycloalkenes has received significant attention. This polymerization is documented, for example in Bielawski et al., Science 2002, 297, 2041-44. Recently, Veige et al. U.S. Patent Application Publication No. 2014/0309389 discloses tridentate pincer ligand supported metal complex of a group 5-7 transition metals that initiate polymerization of alkynes in high yield to macrocyclic polyalkynes. Metal complexes that polymerize alkenes to yield cyclic polyalkenes are desirable. Cyclic norbornene-based macromonomers were polymerized via REMP using cyclic ruthenium catalysts, as described by Boydston et al., J. Am. Chem. Soc. 2008, 130, 12775-82. However, control over both tacticity and the cis/trans ratio is either not reported or is absent. Hence, effective catalysts for the preparation of polymers by stereo-controlled ring-expansion metathesis polymerization are desirable.